Combined search

Use the combined search endpoint in Rummager for site search.

This doesn’t clean up the tests yet – my main aim was to get them passing – so it isn’t the great swathe of red I was hoping for. It does remove the weighting and merging code though, and the tests for that, so that’s a good start.

I also took the opportunity to make the ID for the “departments and policy” tab consistent with the “services and information” tab.